Interpretive Summary: Arcobacter bacteria have gained increased attention and importance as causes of illness in humans who eat pork food products contaminated by Arcobacter. In this study Arcobacter were isolated from pigs at various ages from several different farms of a pig-growing facility and from pigs at a related slaughter plant. Arcobacter types were identified by the presence of specific types of DNA (deoxyribonucleic acid; the materials in cells containing genetic information). Arcobacter of the same types were further differentiated by comparison of the differences in DNA patterns following the treatment of DNA to cut it into smaller pieces. In the groups tested, up to 59% of sows were Arcobacter positive but only 1% of nursing piglets were Arcobacter positive. Infection by Arcobacter progressively increased as the pigs aged and by slaughter-age 100% of the pigs were Arobacter-positive, but upon slaughter only 3% of samples were positive. There was little similarity between DNA patterns for Arcobacter collected from sows and their offspring and between Arcobacter collected from sows in different barns on the same farm and samples from the slaughter plant. The large differences in DNA patterns among pigs from this grower facility suggest an important role for comparison of DNA patterns as an identification and monitoring tool during outbreaks of food poisoning caused by Arcobacter.

Technical Abstract:
Arcobacter spp. were isolated from feces and rectal swabs of nursing sows and developing pigs on a farrow-to-finish swine operation and ceca of market-age pigs at slaughter. Isolates were identified by polymerase chain reaction (PCR) and genotypic fragment patterns were examined by pulsed field gel electrophoresis (PFGE). The incidences of Arcobacter- positive sows ranged from 7% to 57%, while 1% of nursing piglets were positive. Isolation rates of Arcobacter progressively increased with age and 100% of the pens in the finishing barn were Arcobacter-positive. However, only 2.9% of cecal samples from slaughtered pigs were positive. There was little similarity between genotypic patterns for Arcobacter collected from sows and their offspring and between Arcobacter collected from sows housed in different barns on the same farm, as well as between isolates from the slaughter plant and the Yucatan Miniatures maintained at the Food and Feed Safety Research Unit. The amount of variation in genotypic patterns, as detected by PFGE, suggest that Arcobacter collected from this farrow-to-finish operation had undergone genomic rearrangement, common to other members of Campylobacteraceae, during successive passages through pigs. Additionally, the level of genotypic diversity seen among Arcobacter isolates from a single farrow-to-finish swine operation suggests an important role for genotypic phenotyping as a source identification and monitoring tool during outbreaks.